using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using NSubstitute;
using ZB.MOM.WW.ScadaBridge.CentralUI.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Kpi;
using ZB.MOM.WW.ScadaBridge.KpiHistory;

namespace ZB.MOM.WW.ScadaBridge.CentralUI.Tests.Services;

/// <summary>
/// Service-level tests for <see cref="KpiHistoryQueryService"/> (M6 K11). The
/// service fetches a raw series via <see cref="IKpiHistoryRepository.GetRawSeriesAsync"/>
/// and reduces it with <see cref="KpiSeriesBucketer"/>; these tests pin the
/// argument-forwarding contract, the bucketer pass-through, and the
/// <c>maxPoints ?? DefaultMaxSeriesPoints</c> fallback.
/// </summary>
public class KpiHistoryQueryServiceTests
{
    private static readonly DateTime From = new(2026, 5, 20, 10, 0, 0, DateTimeKind.Utc);
    private static readonly DateTime To = new(2026, 5, 20, 11, 0, 0, DateTimeKind.Utc);

    private static IOptions<KpiHistoryOptions> Options(int defaultMax, int rollupThresholdHours = 168) =>
        Microsoft.Extensions.Options.Options.Create(new KpiHistoryOptions
        {
            DefaultMaxSeriesPoints = defaultMax,
            RollupThresholdHours = rollupThresholdHours,
        });

    private static IReadOnlyList<KpiSeriesPoint> Series(params (int minute, double value)[] pts) =>
        pts.Select(p => new KpiSeriesPoint(From.AddMinutes(p.minute), p.value)).ToList();

    [Fact]
    public async Task GetSeriesAsync_ForwardsAllArgs_ToRepository()
    {
        var repo = Substitute.For<IKpiHistoryRepository>();
        var raw = Series((0, 1d), (30, 2d));
        repo.GetRawSeriesAsync(
                "notification-outbox", "queue_depth", "site", "plant-a",
                From, To, Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(raw));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        await sut.GetSeriesAsync(
            "notification-outbox", "queue_depth", "site", "plant-a", From, To);

        await repo.Received(1).GetRawSeriesAsync(
            "notification-outbox", "queue_depth", "site", "plant-a",
            From, To, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_ForwardsNullScopeKey_ForGlobalScope()
    {
        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(Series()));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        await sut.GetSeriesAsync(
            "site-call-audit", "parked_count", "global", scopeKey: null, From, To);

        await repo.Received(1).GetRawSeriesAsync(
            "site-call-audit", "parked_count", "global",
            Arg.Is<string?>(k => k == null),
            From, To, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_ReturnsRawUnchanged_WhenCountWithinMax()
    {
        // raw.Count (3) <= max (200) → bucketer returns the same reference.
        var repo = Substitute.For<IKpiHistoryRepository>();
        var raw = Series((0, 5d), (20, 6d), (40, 7d));
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(raw));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        var result = await sut.GetSeriesAsync("src", "metric", "global", null, From, To);

        // Bucketer returns the raw reference unchanged when raw.Count <= maxPoints.
        Assert.Same(raw, result);
    }

    [Fact]
    public async Task GetSeriesAsync_NullMaxPoints_UsesDefaultFromOptions()
    {
        // raw has 4 points. With DefaultMaxSeriesPoints=2 the bucketer downsamples
        // (4 > 2), so the result is NOT the raw reference and has at most 2 points.
        var repo = Substitute.For<IKpiHistoryRepository>();
        var raw = Series((0, 1d), (15, 2d), (30, 3d), (45, 4d));
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(raw));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 2));

        var result = await sut.GetSeriesAsync(
            "src", "metric", "global", null, From, To, maxPoints: null);

        Assert.NotSame(raw, result);
        Assert.True(result.Count <= 2);
    }

    [Fact]
    public async Task GetSeriesAsync_ExplicitMaxPoints_OverridesDefault()
    {
        // raw has 4 points; explicit maxPoints=10 (>= raw.Count) wins over the
        // option's tiny default of 2, so the bucketer returns the raw reference.
        var repo = Substitute.For<IKpiHistoryRepository>();
        var raw = Series((0, 1d), (15, 2d), (30, 3d), (45, 4d));
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(raw));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 2));

        var result = await sut.GetSeriesAsync(
            "src", "metric", "global", null, From, To, maxPoints: 10);

        // Explicit max (10) >= raw.Count (4) → raw returned unchanged, proving the
        // explicit value beat the default of 2 (which would have downsampled).
        Assert.Same(raw, result);
    }

    [Fact]
    public async Task GetSeriesAsync_EmptySeries_ReturnsEmpty()
    {
        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(Array.Empty<KpiSeriesPoint>()));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        var result = await sut.GetSeriesAsync("src", "metric", "global", null, From, To);

        Assert.Empty(result);
    }

    [Fact]
    public async Task GetSeriesAsync_OpensFreshScopePerCall_OnProductionCtor()
    {
        // The production (IServiceScopeFactory) ctor must resolve a fresh repository
        // per call — same scope-per-query contract AuditLogQueryService upholds, so a
        // chart's auto-load never shares the circuit-scoped DbContext.
        var resolvedRepos = new List<IKpiHistoryRepository>();

        var services = new ServiceCollection();
        services.AddScoped<IKpiHistoryRepository>(_ =>
        {
            var repo = Substitute.For<IKpiHistoryRepository>();
            repo.GetRawSeriesAsync(
                    Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                    Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
                .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(Array.Empty<KpiSeriesPoint>()));
            resolvedRepos.Add(repo);
            return repo;
        });

        await using var provider = services.BuildServiceProvider();
        var sut = new KpiHistoryQueryService(
            provider.GetRequiredService<IServiceScopeFactory>(),
            Options(defaultMax: 200));

        await sut.GetSeriesAsync("src", "metric", "global", null, From, To);
        await sut.GetSeriesAsync("src", "metric", "global", null, From, To);

        // Each call opened its own scope → two distinct repo instances.
        Assert.Equal(2, resolvedRepos.Count);
        Assert.NotSame(resolvedRepos[0], resolvedRepos[1]);
    }

    // ---- Task 5: raw-vs-rollup range routing by RollupThresholdHours ----------------

    private static IKpiHistoryRepository RepoReturningEmptyForBoth()
    {
        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(Array.Empty<KpiSeriesPoint>()));
        repo.GetHourlySeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(Array.Empty<KpiSeriesPoint>()));
        return repo;
    }

    [Fact]
    public async Task GetSeriesAsync_24hWindow_UsesRawPath()
    {
        var repo = RepoReturningEmptyForBoth();
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddHours(24);

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        await repo.Received(1).GetRawSeriesAsync(
            "src", "metric", "global", null, from, to, Arg.Any<CancellationToken>());
        await repo.DidNotReceive().GetHourlySeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_WindowExactlyAtThreshold_UsesRawPath()
    {
        // Boundary is strictly greater-than: exactly 168 h stays on the raw path.
        var repo = RepoReturningEmptyForBoth();
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddHours(168);

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200, rollupThresholdHours: 168));

        await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        await repo.Received(1).GetRawSeriesAsync(
            "src", "metric", "global", null, from, to, Arg.Any<CancellationToken>());
        await repo.DidNotReceive().GetHourlySeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_WindowJustOverThreshold_UsesRollupPath()
    {
        // 169 h (threshold + 1) crosses the boundary → hourly rollup path.
        var repo = RepoReturningEmptyForBoth();
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddHours(169);

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200, rollupThresholdHours: 168));

        await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        await repo.Received(1).GetHourlySeriesAsync(
            "src", "metric", "global", null, from, to, Arg.Any<CancellationToken>());
        await repo.DidNotReceive().GetRawSeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_90dWindow_UsesRollupPath()
    {
        var repo = RepoReturningEmptyForBoth();
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddDays(90);

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        await repo.Received(1).GetHourlySeriesAsync(
            "src", "metric", "global", null, from, to, Arg.Any<CancellationToken>());
        await repo.DidNotReceive().GetRawSeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task GetSeriesAsync_RollupPath_StillBucketsWhenOverMax()
    {
        // A rollup series longer than maxPoints must still be downsampled by the
        // bucketer on top of the rollup read — the bucketer path is unchanged.
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddDays(90);

        // 6 hourly rollup points, spread across the window in ascending order.
        var rollup = Enumerable.Range(0, 6)
            .Select(i => new KpiSeriesPoint(from.AddHours(i * 300), i))
            .ToList();

        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetHourlySeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(rollup));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 3));

        var result = await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        // Routed to the rollup path...
        await repo.Received(1).GetHourlySeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
        // ...and the bucketer still applied (6 rollup rows > max of 3 → downsampled).
        Assert.NotSame(rollup, result);
        Assert.True(result.Count <= 3);
    }

    [Fact]
    public async Task GetSeriesAsync_LongWindow_UsesRollupPath_OnProductionCtor()
    {
        // The production (IServiceScopeFactory) ctor must apply the same threshold
        // routing — a long window resolves the repo from a fresh scope and calls the
        // hourly rollup method.
        var repo = RepoReturningEmptyForBoth();

        var services = new ServiceCollection();
        services.AddScoped<IKpiHistoryRepository>(_ => repo);

        await using var provider = services.BuildServiceProvider();
        var sut = new KpiHistoryQueryService(
            provider.GetRequiredService<IServiceScopeFactory>(),
            Options(defaultMax: 200));

        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddDays(30);

        await sut.GetSeriesAsync("src", "metric", "global", null, from, to);

        await repo.Received(1).GetHourlySeriesAsync(
            "src", "metric", "global", null, from, to, Arg.Any<CancellationToken>());
        await repo.DidNotReceive().GetRawSeriesAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
            Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
    }

    // ---- Task 6: catalog-driven aggregation at the bucketer boundary (R3) -----------

    [Fact]
    public async Task GetSeriesAsync_RateMetric_SumsPerBucket_OnRollupPath()
    {
        // (SiteCallAudit, FailedLastInterval) is a catalog Rate pair. 400 hourly points of
        // value 1 over a 400 h (>168 h) window, maxPoints 200 → 2 points per 2 h bucket →
        // every output value is 2.0 (the summed pair), not 1.0 (last value).
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);
        var to = from.AddHours(400);
        var rollup = Enumerable.Range(0, 400)
            .Select(i => new KpiSeriesPoint(from.AddHours(i), 1d))
            .ToList();

        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetHourlySeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(rollup));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200));

        var result = await sut.GetSeriesAsync(
            KpiSources.SiteCallAudit, KpiMetrics.SiteCallAudit.FailedLastInterval,
            "global", null, from, to);

        Assert.Equal(200, result.Count);
        Assert.All(result, p => Assert.Equal(2.0, p.Value));
    }

    [Fact]
    public async Task GetSeriesAsync_RateMetric_PreservesTotal_AcrossRoutingBoundary()
    {
        // Same total event count (50) served as per-minute deltas on the raw path
        // (window == threshold) and as hourly sums on the rollup path (window just over
        // threshold): the summed chart total must be equal on both routes — the boundary
        // is visually seamless for a Rate metric.
        var from = new DateTime(2026, 5, 1, 0, 0, 0, DateTimeKind.Utc);

        var rawDeltas = Enumerable.Range(0, 10)
            .Select(i => new KpiSeriesPoint(from.AddMinutes(i * 10), 5d)).ToList(); // total 50
        var hourlySums = Enumerable.Range(0, 5)
            .Select(i => new KpiSeriesPoint(from.AddHours(i), 10d)).ToList();        // total 50

        var repo = Substitute.For<IKpiHistoryRepository>();
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(rawDeltas));
        repo.GetHourlySeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<KpiSeriesPoint>>(hourlySums));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 200, rollupThresholdHours: 168));

        var rawResult = await sut.GetSeriesAsync(
            KpiSources.SiteCallAudit, KpiMetrics.SiteCallAudit.FailedLastInterval,
            "global", null, from, from.AddHours(168));     // raw path
        var rollupResult = await sut.GetSeriesAsync(
            KpiSources.SiteCallAudit, KpiMetrics.SiteCallAudit.FailedLastInterval,
            "global", null, from, from.AddHours(169));     // rollup path

        Assert.Equal(50d, rawResult.Sum(p => p.Value));
        Assert.Equal(50d, rollupResult.Sum(p => p.Value));
        Assert.Equal(rawResult.Sum(p => p.Value), rollupResult.Sum(p => p.Value));
    }

    [Fact]
    public async Task GetSeriesAsync_GaugeMetric_KeepsLastValuePerBucket()
    {
        // queueDepth (uncatalogued for this source pairing → Gauge) keeps the existing
        // last-value-per-bucket output unchanged. 4 points, maxPoints 2, raw path.
        var repo = Substitute.For<IKpiHistoryRepository>();
        var raw = Series((0, 1d), (15, 2d), (25, 99d), (35, 5d));
        repo.GetRawSeriesAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string?>(),
                Arg.Any<DateTime>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(raw));

        var sut = new KpiHistoryQueryService(repo, Options(defaultMax: 2));

        var result = await sut.GetSeriesAsync(
            KpiSources.NotificationOutbox, KpiMetrics.NotificationOutbox.QueueDepth,
            "global", null, From, To);

        Assert.Equal(2, result.Count);
        Assert.Equal(99d, result[0].Value); // last value in bucket 0, not a sum
        Assert.Equal(5d, result[1].Value);
    }
}